Grand Challenges in Parkinson's Disease - The Role of Alpha-Synuclein will gather international research leaders, as well as scientists in training and people with Parkinson's disease (PD) to further define the role of alpha-synuclein (?-syn) in PD during an intense two-day forum. Disease-modifying therapies for PD are urgently required to improve the quality of life of people with PD and to reduce the financial burden of PD. With this background, the need for cross-disciplinary scientific discussions focused on ?-syn increases because numerous experimental therapies targeting ?-syn are entering clinical trials. Furthermore, our understanding of the role of ?-syn in PD is rapidly advancing in several disciplines (from genetics to biophysics). We aim to advance PD research by (i) creating a cross-disciplinary forum centered on the pathobiology of ?-syn in order to effectively promote scientific exchange that generates novel ideas for PD treatments; (ii) advancing scientific exchange on ?-syn, beyond that achieved through scientific publications, by ensuring participation of basic science and clinical researchers (from different backgrounds and at different levels of their careers), as well as people with PD; (iii) providing outstanding research training to young researchers and individuals traditionally underrepresented in science by exposing them to international thought leaders in ?-syn research. The 2015 Grand Challenges in Parkinson's Disease conference has been designed to cover as many aspects as possible of the role of ?-syn in PD. Thus, the program is divided in 3 sessions to address the normal functions of ?-syn, its role in the pathobiology of PD and its potential as a clinical biomarker nd therapeutic target. Our focused approach allows experts from various fields to interact in a format that facilitates interactions and discussion; these experts would normally not gather since their expertise often overlaps due to the common denominator in their research. Since 2012, our strategy (characterized by a focused theme, state-of-the-art facilities and excellent logistics) ha ensured the participation of researchers at all levels and from various backgrounds, as well as of people with PD and their family members, in a welcoming environment that guarantees the highest degree of interaction.